MAKING A TWO-PHASE LIQUID/LIQUID OR GAS SYSTEM IN MICROFLUIDICS

• US 20090127123A1
• Filed: 09/22/2006
• Published: 05/21/2009
• Est. Priority Date: 09/22/2005
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Inventors: Raccurt, Olivier, Fouillet, Yves
• Granted Patent: US 8,342,207 B2
• Time in Patent Office: Days
• US Class Current: 205/334
• CPC Class Codes: B01F 25/42 in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
• CPC Class Codes: B01F 33/30 Micromixers
• CPC Class Codes: G02B 3/14 of variable focal length
• CPC Class Codes: Y10T 137/2076 Utilizing diverse fluids
• CPC Class Codes: Y10T 137/2224 Structure of body of device

Abstract

The invention relates to a microfluidic device for making a liquid/liquid or gas biphasic system using a first liquid or a gas and a second liquid, non-miscible with each other, the device having a first hydrophobic surface for the second liquid, the first liquid forming a layer (6) on said first hydrophobic surface. The device comprises means for introducing a drop (7) of the second liquid into the layer of first liquid or gas and in contact with said first hydrophobic surface, and means for displacing the drop on said first hydrophobic surface along a determined path, the device having on the path of the drop, at least one wetting defect causing, upon passing of the drop over this defect, failure of the triple line of contact of the drop on the first hydrophobic surface and inclusion of first liquid (8) or gas into the drop.

The invention also relates to the associated method.

Claims

1. A microfluidic device for making a liquid/liquid or gas biphasic system using a first liquid or a gas and a second liquid, non-miscible with each other, the device having a first hydrophobic surface for the second liquid, the first liquid or gas forming a layer (6) on said first hydrophobic surface, the device comprising means for introducing a drop (7) of the second liquid into the first liquid or gas layer (6) and in contact with said first hydrophobic surface, and means for displacing the drop of the second liquid on said first hydrophobic surface along a determined path, the device having on the path of the drop of the second liquid, at least one wetting defect (5), the wetting defect causing upon the passing of the drop on this defect, failure of a triple line of contact of the drop on the first hydrophobic surface and inclusion (8) of the first liquid or gas in the drop of the second liquid.

2. The microfluidic device according to claim 1, wherein the means for displacing the drop of the second liquid are electrical activation means providing an electro-wetting effect.

3. The microfluidic device according to claim 2, wherein the electrical activation means comprise a succession of electrodes (3) comprised in or on a support (1) having a dielectric layer, a surface of which forms the first hydrophobic surface, the succession of electrodes being positioned along said determined path.

4. The microfluidic device according to claim 2, comprising a second hydrophobic surface positioned facing the first hydrophobic surface so as to form a closed or confined system for the first liquid or gas layer.

5. The microfluidic device according to claim 4, wherein the electrical activation means comprise a counter-electrode comprised in or deposited on an insulating support (4), a surface of which forms the second hydrophobic surface, the counter-electrode being positioned along said determined path.

6. The microfluidic device according to claim 2, wherein the wetting defect (5) is a topological defect present on the first hydrophobic surface.

7. The microfluidic device according to claim 6, wherein the topological defect is selected from the group consisting of a protrusion (5), a hole and a rough area.

8. The microfluidic device according to claim 2, wherein the wetting defect is a wetting defect of the first hydrophobic surface.

9. The microfluidic device according to claim 8, wherein the wetting defect is a permanent defect produced on the first hydrophobic surface or a momentary defect caused on the first hydrophobic surface.

10. The microfluidic device according to claim 3, wherein the wetting defect results from the presence of an additional electrode in the succession of electrodes or from the absence of an electrode in the succession of electrodes.

11. The microfluidic device according to claim 1, wherein the means for displacing the drop of the second liquid are means exerting mechanical action on the drop of the second liquid.

12. The microfluidic device according to claim 11, wherein the means exerting mechanical action on the drop of the second liquid comprise a pump.

13. The microfluidic device according to claim 11, wherein the wetting defect is a topological defect present on the first hydrophobic surface.

14. The microfluidic device according to claim 13, wherein the topological defect is selected from the group consisting of a protrusion, a hole and a rough area.

15. The microfluidic device according to claim 11, wherein the wetting defect is a wetting defect of the first hydrophobic surface.

16. The microfluidic device according to claim 15, wherein the wetting defect is a permanent defect produced on the first hydrophobic surface or a momentary defect caused on the first hydrophobic surface.

17. The microfluidic device according to claim 11, comprising a second hydrophobic surface positioned facing the first hydrophobic surface so as to form a closed or confined system for the first liquid or gas layer.

18. The microfluidic device according to claim 1, comprising a second hydrophobic surface positioned facing the first hydrophobic surface so as to form a closed or confined system for the drop of second liquid, the first hydrophobic surface and the second hydrophobic surface also confining said first liquid and a third liquid, non-miscible with each other, the second hydrophobic surface also having a wetting defect positioned relatively to the wetting defect of the first hydrophobic surface, to the first liquid and to the third liquid so that the passing of the drop of the second liquid on the wetting defects causes inclusion of the first liquid and inclusion of the third liquid in the drop of the second liquid.

19. The microfluidic device according to claim 18, wherein the first liquid (66) and the third liquid (76) are positioned in succession in the device, relatively to the passing of the drop (67) of second liquid, the first liquid (66) being in contact with the wetting defect (65) of the first hydrophobic surface (62), the third liquid (76) being in contact with the wetting defect (75) of the second hydrophobic surface (64).

20. The microfluidic device according to claim 18, wherein the first liquid (86,106) and the third liquid (96,116) are positioned, superposed in the device, the drop of second liquid (87,107) simultaneously passing into the first liquid and the third liquid, the first liquid (86,106) being in contact with the wetting defect (85,105) of the first hydrophobic surface (82,102), the third liquid (96,116) being in contact with the wetting defect (95,115) of the second hydrophobic surface (84,104).

21. The microfluidic device according to claim 3, wherein said at least one wetting defect is formed by a hole (125) in one of the electrodes (123₂).

22. The microfluidic device according to claim 21, comprising several holes in one of the electrodes (143₂), the holes forming as many wetting defects and being positioned according to a matrix arrangement.

23. The microfluidic device according to claim 3, wherein said at least one wetting defect is formed by an additional electrode (135′

) positioned inside one of said electrodes (133₂) and without any electric contact therewith.

24. The microfluidic device according to claim 23, comprising several additional electrodes (155) inside one of said electrodes (153₂) and without any electric contact therewith, said additional electrodes (155) forming as many wetting defects and being positioned according to a matrix arrangement.

25. A method for making a liquid/liquid or gas biphasic system using a first liquid or a gas and a second liquid non-miscible with each other, comprising:

forming a first liquid or gas layer (6) on a first hydrophobic surface,

introducing a drop of the second liquid (7) within the first liquid or gas and in contact with said first hydrophobic surface,

displacing the drop of the second liquid (7) on said first hydrophobic surface along a determined path so that the drop of the second liquid encounters at least one wetting defect (5), upon passing of the drop of the second liquid over this defect, failure of a triple line of contact of the drop of the second liquid (7) on the first hydrophobic surface and inclusion of the first liquid (8) or gas in the drop of the second liquid.

26. The method according to claim 25, wherein the displacement of the drop of the second liquid is obtained by electrical activation providing an electro-wetting effect.

27. The method according to claim 25, wherein the displacement of the drop of the second liquid is obtained by mechanical action on the drop of the second liquid.